In diagnosis and therapeutic method of biomedical science, especially in applications of detecting tumor cells, stem cells, embryos or bacteria, how to separate cells effectively and not to destroy cells are quite important. Hence, controlling and analyzing technologies applied in biomolecule field have been widely studied in recent years.
Conventional controlling technology such as optical tweezers, electrophoresis, dielectrophoresis, travelling-wave dielectrophoresis, electrorotation, magnetic tweezers, acoustic traps and hydrodynamic flows cannot reach high resolution and high flux at the same time. Although the technology of optical tweezers can achieve high resolution so as to capture single particle, the operation area is only about 100 μm and the light energy intensity is up to 107 W/cm2. It is easy to overheat in local area and cause cells death or deactivation. Therefore, optical tweezers is not suitable for long time operation. Besides, although electrophoresis force and dielectrophoresis force can achieve high flux, they cannot control single cell due to lack of space resolution. In addition, the dielectrophoresis flow field chip only has one function (for example, transmitting function or separating function) in general. While designing the dielectrophoresis flow field chip with different flow field, it needs to redesign a set of light mask and execute many complicated manufacturing process such as deposition, photolithography and etching to manufacture fixed electrodes. Therefore, it demands considerable cost, time and human resource.
Accordingly, a controlling technology using an optically-induced dielectrophoresis force to control particles performing dielectrophoretic motion has been provided. It mainly utilizes an optically-induced dielectrophoresis image system to project an optical pattern on the optically-induced dielectrophoresis operation platform having photoconducting material and to change dielectrophoresis flow field immediately according to the appearance and trajectory speed of the image so as to achieve the features of controlling single cell and identifying a large number of cells within a short period of time. The controlling technology using the optically-induced dielectrophoresis force can achieve high resolution and high flux and simplify the complicated processes of precondition for bio-specimen previously.
However, a projection path of the conventional optically-induced dielectrophoresis image system is quite complicated. The projection path is from a projector aiming at one object lens to a chip, and then the light projected to the chip aims at another object lens to couple with a charge-coupled device so as to form an image. Besides, because a displaying image cannot be projected on the chip completely, the full displaying image cannot be watched in the conventional optically-induced dielectrophoresis image system.